Core diffuser for deoiler/breather

Abstract

A breather assembly for use with a gas turbine engine includes a static housing for accepting a fluidic mixture of substances, a rotatable separator having one or more fluid inlets and arranged about an axis of rotation, an exhaust outlet defined in the housing and positioned coaxially with the rotatable separator to accept fluidic exhaust from the rotatable separator, and a static diffuser supported by the housing at or near the exhaust outlet downstream from the rotatable separator. A portion of the static diffuser extends within the rotatable separator. The static diffuser includes a flow-straightening structure configured to reduce vortex flows in fluid flows passing through the exhaust outlet.

The invention claimed is: 
     
       1. A breather assembly for use with a gas turbine engine, the assembly comprising:
 a static housing for accepting a fluidic mixture of substances; 
 a rotatable separator having one or more fluid inlets and arranged about an axis of rotation; 
 an exhaust outlet defined in the housing and positioned coaxially with the rotatable separator, wherein the exhaust outlet accepts fluidic exhaust from the rotatable separator; and 
 a static diffuser supported by the housing at or near the exhaust outlet downstream from the rotatable separator, wherein a portion of the static diffuser extends within the rotatable separator, the static diffuser including a flow-straightening structure configured to reduce vortex flows in fluid flows passing through the exhaust outlet. 
 
     
     
       2. The assembly of  claim 1 , wherein the static diffuser is supported by the static housing in a cantilevered configuration. 
     
     
       3. The assembly of  claim 1 , wherein the static diffuser comprises:
 a substantially cylindrical support tube; and 
 a plurality of diffuser stage plates supported by the support tube, each diffuser stage plate defining a plurality of flow straightening passages. 
 
     
     
       4. The assembly of  claim 3 , wherein the flow straightening passages are each configured to redirect fluid flow from a generally radial direction to a generally axial direction. 
     
     
       5. The assembly of  claim 3 , wherein the flow straightening passages each define an inlet at a circumference of the respective diffuser stage plate and an outlet at a radially inward portion of the respective diffuser stage plate. 
     
     
       6. The assembly of  claim 5 , wherein at least one of the diffuser stage plates defines a plurality of pass-through openings aligned with the outlets of the flow straightening passages of an adjacent one of the diffuser stage plates located immediately upstream. 
     
     
       7. The assembly of  claim 3 , wherein the static diffuser further comprises:
 a cruciform flow guide at a downstream end of the support tube. 
 
     
     
       8. The assembly of  claim 3  and further comprising:
 a separator shaft secured to the rotatable separator and having one or more radial openings, wherein the support tube is positioned coaxially with and at least partially within the separator shaft; and 
 one or more inlets defined in the housing for accepting a fluidic mixture of oil and air, wherein at least one of the one or more inlets has a generally tangential orientation to impart circumferential rotational motion to the fluidic mixture of oil and air entering the housing. 
 
     
     
       9. The assembly of  claim 3 , wherein a diameter of each of the diffuser stage plates is sequentially larger in the downstream direction. 
     
     
       10. The assembly of  claim 3 , wherein the flow straightening passages each define an outlet, and wherein the outlets of each respective diffuser stage plate are at a different radial location. 
     
     
       11. A method for reducing adiabatic condensation of oil in gas turbine engine exhaust streams containing an oil and air mixture, the method comprising:
 directing a fluid to a rotating separator assembly; 
 separating oil from the fluid within the rotating separator assembly to produce a remaining portion of the fluid; 
 directing the remaining portion of the fluid radially inward from the rotating separator assembly to a static diffuser assembly; and 
 converting rotational momentum of the remaining portion of the fluid into axial movement with the static diffuser assembly to reduce vortex formation in the fluid. 
 
     
     
       12. The method of  claim 11 , wherein step of the converting rotational momentum of the remaining portion of the fluid into axial movement with the static diffuser assembly is performed over a plurality of stages that distribute the remaining portion of the fluid across different radial locations. 
     
     
       13. The method of  claim 11  and further comprising:
 dividing the remaining portion of the fluid into a plurality of subflows directed into a plurality of stages of the static diffuser assembly. 
 
     
     
       14. The method of  claim 11  and further comprising:
 passing the remaining portion of the fluid through a cruciform flow guide at a downstream end of the static diffuser assembly. 
 
     
     
       15. The method of  claim 11 , wherein the fluid pressure of the remaining portion of the fluid downstream of the static diffuser assembly is substantially equal at radially inward and radially outward locations. 
     
     
       16. The method of  claim 11 , wherein the step of separating oil from the fluid within the rotating separator assembly comprises passing the fluid through a rotating metallic foam structure. 
     
     
       17. A gas turbine engine assembly comprising:
 a housing; 
 one or more inlets defined in the housing for accepting a fluidic mixture of oil and air, wherein at least one of the one or more inlets has a generally tangential orientation to impart circumferential rotational motion to the fluidic mixture of oil and air entering the housing; 
 a rotatable oil separator having one or more fluid inlets and arranged about an axis of rotation to accept the fluidic mixture of oil and air; 
 a breather outlet defined in the housing and positioned coaxially with the rotatable oil separator, wherein the breather outlet accepts fluidic output from the rotatable oil separator after oil has been removed from the fluidic mixture; and 
 a static diffuser supported by the housing in a cantilevered configuration and in fluid communication with both the breather outlet and the rotatable oil separator, the static diffuser comprising:
 a substantially cylindrical support tube; 
 a plurality of diffuser stage plates supported by the support tube; and 
 a plurality of flow straightening passages defined in each diffuser stage plate, wherein each flow straightening passage is configured to redirect fluid flow from a generally radial direction to a generally axial direction to reduce vortex flows. 
 
 
     
     
       18. The assembly of  claim 17 , wherein the flow straightening passages each define an inlet at a circumference of the respective diffuser stage plate and an outlet at a radially inward portion of the respective diffuser stage plate, wherein at least one of the diffuser stage plates defines a plurality of pass-through openings aligned with the outlets of the flow straightening passages of an adjacent one of the diffuser stage plates located immediately upstream, and wherein the outlets of each respective diffuser stage plate are at a different radial location. 
     
     
       19. The assembly of  claim 17 , wherein the static diffuser further comprises:
 a cruciform flow guide at a downstream end of the support tube. 
 
     
     
       20. The assembly of  claim 17  and further comprising:
 a separator shaft secured to the rotatable separator, wherein the support tube is positioned coaxially with and at least partially within the separator shaft, the separator shaft including one or more radial openings.